This invention relates to a library device, and more particularly, to a magnetic tape cartridge recognition device in a magnetic tape library apparatus which is connected to a large computing system as a large-capacity storage device.
To process growing volumes of information in computing systems, many fully-automatic library devices that do not require operators are appearing these days, as a means of storing large volumes of information. These library devices use single-reel tape cartridges as storage media, and handle cartridges fully automatically.
To automate cartridge transportation, a fully-automatic library has a media handling robot called an accessor as a cartridge transporting device which can be moved in the library device. While moving on a lengthwise rail in the library device, this accessor inserts or ejects a cartridge and mounts a cartridge on or demounts one from a data recording and regenerating device automatically.
To insert a cartridge into or eject one from this automated library device, the address of each cartridge frame (hereinafter, called cell) should be related to the cartridge to be stored. For cartridge identification, bar codes on the cartridges are read and the read data is managed.
FIG. 1 shows an example of a conventional library device 2. The library device 2 has an accessor unit 9, a drum unit 10, and a drive unit 12 which can be installed in a flexible layout.
FIG. 2 is a cutaway view showing the internal structure of the library device 2. The library device 2 has two cartridge access stations 4 (CAS), one on the front side of the left accessor unit 7 and the other on the front side of the right accessor unit 9.
Each cartridge access station 5 has a cartridge entry 6 and a cartridge exit 8. The cartridge entry 6 and exit 8 can rotate 180 degrees around their vertical axes.
Drum units 10a, 10b have cell drums 15a, 15b each containing several cells. The cells drums 15a, 15b each consist of cell segments 17a-17f. The cell segments 17a-17f have n-stage cells in three rows.
Each cell accommodates a cartridge that stores magnetic tape. The cartridge can be an I3480-type magnetic tape cartridge or any other suitable device. By opening the direct entry exit (DEE) door 64 of the drum unit 10a, the operator can insert a cartridge into, or eject one from one of the cell segments 17a to 17f located in front of the DEE door 64.
Four drive units 12a-12d record and regenerate information on magnetic tape stored in each cartridge. Each drive unit 12a to 12d of the library device 2 has several tape drive units (for example, four tape drive units in each drive unit). These tape drive units have cartridge entry-exit ports. A cartridge entry-exit port is a plane including the X axis, tilted by 5.5 degrees from the vertical plane relative to the Y axis.
The housing 4 accommodates PC boards for controlling the cartridge access station 5, drum units 10a, 10b, drive units 12a-12d, and two accessor units 14.
The accessor 14 has a hand assembly 16 which can be moved vertically (direction Y in the figure) along the vertical column 18 projecting from the rail base 32. The rail base 32 enables the accessor 14 to move horizontally (direction X in the figure) along the guide rail (X rail) 20. The accessor 14 is an X-Y move mechanism. A sensor 163 is attached to the rail base 32 of the accessor 14 to detect the position flag 165 on the accessor unit 9.
FIG. 3 is a cutaway view showing the internal structure of a drum unit 10a in the library device 2. The drum unit 10a contains a drum 3 which is driven by a motor (not illustrated in the figure). The drum 3 contains seven rows of cell segments (17a to 17f in FIG. 2). The cell segments 17 of each row accommodate several DEE magazines 30 each having cells 5 in three rows and seven stages. The DEE magazine 30 can accommodate up to 21 cartridges 1. The operator can insert a DEE magazine 30 in each cell by opening the DEE door 64 of the drum unit 10a from the DEE operation panel 31.
The drum unit 10a contains a DEE controller 33, a power sequencer 34, a power supply 35 for DEE and LBR, a drum power supply 36, an AMC interface 37, a driver unit 38, a drum controller 39, a local bar code reader (LBR) assembly 40, a controller 41 for local bar code reader, a vertical column base 78, and a bar code reader 68 for reading the back bar code label 1B of a cartridge 1. The drum unit 10a also has an operator panel 43 on the front.
The local bar code reader assembly 40 is placed at the corner adjacent to the downstream DEE door in the rotating direction of the housing drum 3 of the square-column-shaped drum unit 10a. Since the drum unit 10a uses a polyhedral rotating cell drum 15a, a local bar code reader 68 can be mounted on a corner of the housing.
The accessor 14 accesses a cell 50 on the cell drum 15a through a port on the back of the drum unit 10a. Before the cell segment 17 where the operator inserted or ejected a cartridge reaches the back of the drum unit 10a, the local bar code reader 68 can read a bar code label on the cartridge 1.
FIGS. 4(a) and 4(b) show only the local bar code reader 40 in FIG. 3. The bar code reader 68 on the local bar code reader 40 is linked to the slide guide 76 and moves together with the guide. This slide guide 76 moves back and forth along the slide rail 74. The slide rail 74 is attached to the vertical column base 78. The vertical column base 78 supports the bar code reader 68, lower pulley 72, upper pulley 106, pulse motor 70, and slide rail 74. There is a timing belt 108 between the lower pulley 72 and upper pulley 106. The timing belt 108 is secured on the slide guide 76 of the bar code reader 68.
A balancing weight 110 is attached to the timing belt 108 to counterbalance the weight of the bar code reader 68. This bar code reader 68 can rotate around the slide guide 76 in the axial direction. The motor 82 on the slide guide 76 drives the bar code reader 68.
The pulse motor 70 rotates the lower pulley 72. Rotation of the lower pulley 72 is conveyed through the timing belt 108 and moves the slide guide 76 along the slide rail 74 where the bar code reader 68 is mounted. A sensor secured on the slide guide 76 detects the flags of the position flag bar. Flags detected by the sensor are counted to determine the position of the slide guide 76 on the vertical column base 78. These sensors and the position flag bar configure the position detection mechanism of the bar code reader 68.
The flange 78a at the bottom of the vertical column base 78 is secured on the base of the drum unit 10a with screws, and the flange 78b at the top is secured on the top of the drum unit 10a. Therefore, the local bar code reader 40 can be disengaged from the drum unit 10a if the screws affixed to the flanges 78a, 78b are removed.
The controller 41 on the vertical column base 78 sends control signals to control the bar code reader 68. These control signals reach the bar code reader 68 through the signal cable 42. By connecting or disconnecting a connector (not illustrated), the bar code reader 68 and the signal cable 42 can be connected or disconnected. The controller 41 sends drive signals to the drum motor (not illustrated) of the cell drum 15 through another signal cable (not illustrated).
FIG. 5 shows the structure of the accessor 14 shown in FIG. 2. The accessor 14 consists of a rail base 32 which moves along the lengthwise guide rail (X rail) of the library device 2, a vertical column 18 projecting from the rail base 32, and a hand assembly 16 which moves along the vertical column 18. The accessor 14 transports a cartridge along the X rail 20.
The rail base 32 has a drive roller 19A and a follower roller 19B on each end to hold the X rail between them. The drive roller 19A is driven by a motor 25X on the rail base 32. When the drive roller 19A rotates, the rail base 32 moves on the X rail.
The vertical column 18 has one pulley (not illustrated) each at the mounting end and at the free end on the rail base 32. There is a timing belt between the two pulleys. This belt 21 is driven by the motor 25Y on the vertical column 18. The vertical column 22 has a guide rail to move a hand assembly 16.
The hand assembly 16 is mounted on a carriage 24 which moves vertically along the guide rail 22 formed on the vertical column 18 of the accessor 14. The carriage 24 has a motor 25Z and a PC board 29 for controlling the motor. Together with the motor 25Z and PC board 29, this carriage 24 moves along the guide rail 22 in the Y-axis direction.
The motor 25Z turns the mount base 27 of the hand assembly 16 around a vertical axis parallel with the Y axis through the timing belt 26 linked to the output axis of the motor. In other words, the motor 25Z oscillates the mount base 27 in the cartridge moving direction.
On the mount base 27 is positioned a hand unit 23 to hold the cartridge, a motor 28A for moving the hand unit 23 in the direction indicated by arrow Z, and a motor 28B for tilting the hand unit 23 against the mount base 27. The five motors 25X, 25Y, 25Z, 28A, 28B enable the hand unit 23 of the hand assembly 16 to move freely in three dimensions.
FIGS. 6 (a) to 6 (c) show the structure of a cartridge 1 used in the library device 2 as storage media. For example, the cartridge 1 can be a 12.7-mm-wide magnetic tape of a high recording density wound around a reel and accommodated in a casing 1a. The tape 1b has a leader block 1c at its front end for threading. When the cartridge 1 is ejected, this leader block 1c is in the casing 1a. The reel is secured by a lock mechanism to prevent vibrations from slackening the tape during transportation.
The cartridge 1 has a writable label L0 on the top 1T and bar code labels L1, L2 on the back 1B and one side 1S. FIG. 7 (a) shows an example of bar code label L1 to affix to the back 1B of the cartridge 1, and FIG. 7 (b) shows an example of bar code label L2 to affix to the side 1S of the cartridge 1.
FIG. 8 shows an example of hardware structure for the library device 2. In the figure, the library device 2 is connected to four host computers 301-304. The host computers 301-304 are connected to the library device 2 through their channel interface buses 311-314. The buses 311-314 may be block multiplexer channel or SCSI interfaces. For example, four directors 321-324 are installed on the library device 2. Two directors 321, 323 have channels A to D and the other two (322, 324) have channels E to H.
The channel interface bus 311 from the host computer 301 is connected to channel A of the directors 321, 323 and the channel interface bus 312 from the host computer 302 is connected to channel B. The channel interface bus 313 from the host computer 303 is connected to channel E of the directors 322, 324 and the channel interface bus 314 from the host computer 303 is connected to channel F. Channels C and D of the directors 321, 323 and channels G and H of the directors 322, 324 are not used.
Two channels a and b are prepared on the terminal side of the directors 321 -324. Channel a is for the magnetic tape units 340, 350 (MTUs) and channel b is for accessor control. The directors 321,322 share eight MTUs commonly connected through device buses 331, 332 of channel a. Therefore, the directors 321, 322 can access, for write or read operations, the MTUs 340 through channel a. The eight MTUs 340 are located in the drive units 12a-12c. 
The directors 323, 324 share eight MTUs connected commonly through device buses 333, 234 of channel a. Therefore, the directors 323, 324 can make write or read access to the MTUs 350 through channel a. The eight MTUs 350 are located in the drive units 12b, 12d. 
The device interface bus 338 from channel b of the directors 321, 322 is connected to channel a of the accessor controller 328. The device interface bus 339 from channel b of the directors 323, 324 is connected to channel b of the accessor controller 328.
The accessor controller 330 is a spare device where the device interface bus 338 from channel b of the directors 321, 322 is connected to channel a and the device interface bus 339 from channel b of the directors 323, 324 is connected to channel b.
The accessor controllers 328, 330 execute processing in accordance with an instruction received from one of the directors 321-324. Under the accessor controller 330 are machine controllers 351,352 for controlling the accessors 14 of the accessor units 7, 9. Under the accessor controller 328 are drum controllers 361, 362 for controlling the cell drums 15a, 15b of each of the drum units 10a. The accessor controllers 328, 330, machine controllers 351, 352, and drum controllers 361, 362 are in the accessor units 7, 9. For ease of understanding, FIG. 8 shows two cell drums 15a, 15b. 
The machine controllers 351, 352 and drum controllers 361, 362 are also connected commonly to the accessor controller 330. When a library device 2 I/O request is received for job execution, a host computer 301-304 specifies a logical device address and issues to the directors 321, 322 through its own allocated channel a move command instructing the I/O device to start operation. Once a normal receive response to this move command is received from the director side, the host computer transfers data bytes (command parameters) as media transportation information.
The data bytes containing the move-from and move-to addresses of the cartridge are stored in the queuing table of the accessor controller 328. If the accessor 14 of an accessor unit 7, 9 is found to be idle, the accessor controller 328 fetches the move-from and move-to addresses of the move command from the queuing table and instructs a machine controller 351, 352 to move the accessor 14. If necessary, the accessor controller 328 also instructs a drum controller 361, 362 to rotate a cell drum 15a. 15b. 
By referencing the conversion table, the accessor controller 328 converts move-from and move-to cell addresses fetched from the queuing table into a cell drum rotation angle !!XX!! and an accessor coordinate position (X, Y). The cell drum is then turned by the rotation angle !!XX!! and the accessor is moved to the position (X, Y).
FIGS. 9 (a) and 9 (b) show the structure of the cell drum 15 and the position of the local bar code reader 40. As FIG. 3 shows, the cell drum 15 has seven faces and has a capacity of 21 cartridges. The local bar code reader 40 is positioned at one side of this cell drum 15. The bar code reader shown in FIG. 4 checks each cell in the cell drum 15 for a cartridge 1 while being guided by the slide rail 74, and reads information from the back or side bar code label of the cartridge 1.
The library device 2 having the above structure identifies each cartridge 1 with a bar code as explained next. Under conventional technology, when a DEE (entry or exit) start command is received from a host computer, all of the drum cells in a library device are made available for the execution by the operator of the entry or exit procedure for cartridges in units of rows. After inserting or ejecting cartridges, the operator had to press the DEE end switch to report the end of DEE work to the host computer.
FIG. 10 shows the conventional cartridge entry procedure by the operator. In step 101, the operator confirms a DEE start instruction from the host computer. The operator then opens the DEE door in step 102, inserts cartridges in step 103, and closes the DEE door in step 104. The cell drum rotates to the next three rows. Step 105 is to verify that cartridges were inserted into all of the rows of the cell drum. If the cartridge entries are not yet completed, the procedure from step 102 to 104 is repeated. Once the completion of cartridge entries has been confirmed, the procedure advances to step 106. The operator then presses the DEE end switch and reports the end of DEE work to the host computer.
When the end of DEE work is reported, the host computer issues a bar code read command. In accordance with this command, the local bar code reader 40 reads the bar code label on the back of a specified cartridge and reports the bar code data each time a cartridge is detected. In the conventional library system, a host computer had to issue the same number of bar code read commands as there were cells contained in the row of the drum.
FIG. 11 shows the conventional procedure for a host computer to read a bar code label on each cartridge.
Step 201 is to check whether the DEE switch was pressed. If the DEE switch was not pressed, this routine terminates. If the DEE switch was pressed, the procedure advances to step 202 where the host computer issues a read instruction each time a cartridge is detected to read the bar code label on the cartridge. In step 203, the bar code reader (BR) (68) moves to the position of a specified cartridge 1 and reads the back bar code label of the cartridge using a laser beam.
Step 204 is to check whether the back bar code label of the cartridge 1 could be read. If the bar code could be read, the procedure advances to step 205. There the system checks whether the read bar code is the bar code on the no-cartridge label affixed inside each cell in the cell drum. If the bar code is not the bar code on the no-cartridge label, the procedure advances to step 206 where data from the back bar code label of the cartridge 1 is reported to the host computer and this routine terminates. If the bar code is the bar code on the no-cartridge label, the procedure advances to step 207 where the absence of a cartridge is reported to the host computer and this routine terminates.
If the bar code could not be read in step 204, the procedure advances to step 208 where the bar code reader 68 moves to the master bar code label and reads the master bar code. Step 209 is to check whether the master bar code could be read. If the master bar code could be read, the procedure advances to step 210 where the absence of a bar code label on the cartridge is reported to the host computer and this routine terminates. If the master code could not be read, the procedure advances to step 211 where a fault of the bar code reader 68 is reported to the host computer and this routine terminates.
There are some problems with the known devices just described. For example, a local bar code reader can read a bar code label on the back but not on a side surface of a cartridge in the conventional cartridge check procedure by a host computer. If the local bar code reader becomes faulty, cartridges cannot be inserted from the cell drum because only one bar code reader is assigned to each cell drum. Moreover, even if the local bar code reader fails to read a bar code label, the bar code reader at the accessor does not retry reading because the local bar code reader and the accessor are not interlocked.
There are more problems with known devices. Each time a bar code label is not detected on a cartridge, the master bar code label is checked for comparison to see whether the cartridge is not labeled or the local bar code reader is faulty. Also, the local bar code reader reads bar code labels only on cartridges when an instruction is received from the host computer after the operator completes the DEE work.
Since bar code label data is reported to the host computer each time a cartridge is read, the host computer issues the same number of label read instructions as there are cells contained in the row of the drum. This invention solves these problems and disadvantages.
Thus, this invention includes at least the following features:
(1) Providing a library device which can read the side bar code labels of cartridges;
(2) Providing a library device which allows cartridge entries from a cell drum even when one bar code reader becomes faulty;
(3) Providing a library device where the two bar code readers are interlocked with the accessor so that one bar code reader retries reading if the other bar code reader fails to read a bar code label;
(4) Providing a library device which reduces the bar code label read time after the DEE work by the operator;
(5) Providing a library device which reduces the time for reporting bar code label data to the host computer; and
(6) Providing a library device which reduces the time for checking a non-labeled cartridge.
Accordingly, one object of this invention is to provide a library device which can accurately read bar code labels on cartridges, including labels on the sides of cartridges.
A second object of this invention is to provide a library device which can insert cartridges from a cell drum even when one local bar code reader is faulty.
A third object of this invention is to provide a library device which can identify the bar code contents even if a local bar code reader fails to read a bar code label.
A fourth object of this invention is to provide a library device which can reduce the bar code read time after the operator finishes direct entry/exit (DEE) work.
A fifth object of this invention is to provide a library device which can reduce the time for reporting bar code data to the host computer.
A sixth object of this invention is to provide a library device which can reduce the time for checking a cartridge for a label.
The first form of this invention, which achieves the first purpose above, is a large-capacity storage device connected to a computing system with cartridges as storage media. A data recording and regenerating device for writing data into, and reading it from cartridges is provided, with a cartridge entry-exit device for inserting and ejecting cartridges, cells for storing cartridges, a media transporting device for transporting cartridges between the cell plates and the data recording and regenerating device, and a label reading device at the cell drum for reading labels on cartridges.
A laser guidance means is provided on the wall beside the cartridge in each cell of the cell drum to guide laser beams from the label reading device to the side label of each cartridge for reading by the device. The laser guidance means may be a mirror, a prism or the like. The label reading device may have parallel moving mechanisms behind the cartridges in the cells which can move to the wall side to read other labels.
This laser guidance means enables the label reading device to read a label on one side of a cartridge. Then data read from the back label of a cartridge can be compared with that read from the side label of the same cartridge. It is possible to output a cartridge error signal if the data does not match. In addition, it is possible to instruct a reading of data from the side label of the same cartridge if the device failed to read the back label.
The second form of this invention achieves the second purpose of the invention. It is a large-capacity storage device connected to a computing system with cartridges as storage media, equipped with a data recording and regenerating device for writing data into, and reading it from cartridges. A cartridge entry-exit device is provided for inserting and ejecting cartridges, with cells for storing cartridges, fixed frame plates, a media transporting device for transporting cartridges between the cells and the data recording and regenerating device, and a label reading device at the cell drum for reading labels on cartridges. The label reading device has a rail in the vertical direction of the cell drum, first and second bar code readers which can move on the rail, and control circuits for controlling the bar code readers. A memory can be provided which stores cartridge locations as the cartridges are placed in the storage device.
By adding various functions to the control circuits, the following operations can be realized:
(1) The library device may have a means of controlling the first and second bar code readers in parallel. The first and second bar code readers can then read cartridge labels simultaneously.
(2) The library device may have a means of detecting a positioning error and retrying positioning for the first and second bar code readers. If a positioning error occurs in the first or second bar code reader, the bar code reader is returned to the home position and positioning is retried.
(3) The library device may have a means of detecting an operation error and issuing a retraction or continuous read instruction for the first and second bar code readers. If an operation error occurs in the first or second bar code reader, the bar code reader is retracted to the retraction position and the other bar code reader continues the read processing.
(4) The library device may have a means of recording the time for the scheduled maintenance of a bar code reader and issuing a move or continuous read instruction for the first and second bar code readers. If the time for performing the scheduled maintenance for the first or second bar code reader arrives, the bar code reader moves to the maintenance position and the other bar code reader continues the read processing.
(5) The library device may have a means of detecting a read error and issuing a retraction or substitute read instruction. If a read error occurs in the first or second bar code reader, the other bar code reader retracts the current one from the label read position and continues the read processing. If the substitute read processing succeeds, the initial library device is regarded as abnormal. If the substitute read processing fails, the cartridge or either of the bar code readers is reported as abnormal.
The third embodiment of this invention is a large-capacity storage device based on the first embodiment, where the media transporting device consisting of a gripping mechanism for gripping a cartridge and a mechanism surrounding frame equipped with a bar code reader for reading data from a label on the gripped cartridge has another bar code reader at a frame position opposing the side of a cartridge in a cell gripped by the gripping mechanism.
This other bar code reader enables the media transporting device to read both the back and side bar code labels on a cartridge. If no label is detected on a cartridge, the label reading device outputs an instruction signal to the media transporting device for rechecking the cartridge for a label. In accordance with this instruction, the media transporting device grips the cartridge for the two bar code readers to check the cartridge for a label.
The fourth object is realized by a library device of the above forms, where the label reading device is installed at a downstream rotation side of the cell drum against the cartridge entry-exit door for the cell drum. Consequently, when a cartridge is inserted through the door and the cell drum rotates to another cartridge entry position, the label reading device can read the first cartridge. This reduces the bar code label read time after the operator finishes DEE work.
In the fifth embodiment of this invention, a library device of the above forms is again provided, where the label reading device stores bar code label data from a single row of cells (block) once in the memory and transfers the data to the host computer together at the end of a block. This reduces the time for reporting bar code data to the host computer.
The sixth object of this invention is achieved by providing a library device of the fifth embodiment, where the label reading device stores any detected error in the memory when reading cartridge labels and reads the master code label at the end of a block to see whether a bar code label exists. This reduces the time for checking a non-labeled cartridge.